This is an interesting development. I am not suprised that this worked, since in the AR-15 design most of the stress is contained in the upper receiver. What is interesting is that the lower receiver is what is licensed.

I can speak to the implications in Illinois. We do not register particular guns. Yes, you go through a process when you buy a gun in the state from a retailer. On the other hand, buying a gun from an individual does not require a check with the authorities. Generally, you should keep a record of the sale for ten years (this is a federal requirement). What we do have here is a Firearms Owners ID (FOID). This is what allows an individual to possess a firearm. You are not allowed to own a full auto gun without a Class 3 license (again, a federal regulation). I have known people to make their own hunting guns, for long range hunting. They did not have to register them. They, as a registered gun owner, are permitted, not the gun. As with most laws, the enforcement is after the fact. If you drive a car and you kill someone (a much more likely event than ine using a gun) then you are prosecuted after the fact. Little is done to stop people, although there is technology coming that might help.

Enough of the legal rap. What is interesting is that, through computer technology, we are freeing ourselves from the dependence on large organization for many of the things we consume. Think of the production and distribution of music, and now video. With 3D printing, this is extending to many physical products. Change it is a coming!

Naperlou: I like your synopsis of where 3D printing is going in terms of freeing us up from a dependance on companies for consumables. As much as I found this example pretty compelling from the standpoint of what the technology is capable of, I definitely am not on board with giving people the tools to produce their own firearms or other weapons. Laws or no laws, it just opens the door to bad behavior.

All technological improvements come with a downside. Automobiles, for example have pretty consistently cost about 40,000 lives a year in the US for the last couple of generations. If that "cost" was known at the outset, how anxious would people have been to embrace the technology? That being said, I'm not an advocate of making it easier for the average Joe or Jane to get their hands on potentially lethal products, so this advent certainly opens up a can of worms for law enforcement. Where and how you draw the line gets more complicated as technology advances. This manufacturing technique could potentially be used to build grenades, land mines, maybe even small missiles. No doubt about it, this article just highlights the Pandora's box that comes with new technologies.

I guess this was inevitable, but I have a hard time thinking it's an example of either consumer or creative freedom. Bad behavior is already out there and this will help make it harder to control: if criminals can make their own entirely unregulated automatic weapons, bloodshed is likely to increase. Let alone land mines, and missiles, as Scott points out.

This is a scary development. Sounds like it also could be dangerous for users. But this has to be measured against the ease of obtaining firearms. That ease may make this technology unnecessary for those who want guns. Who is really getting turned down when buying guns at shows or from private owners?

As with all innovative products, individuals who exploit them present the Dark Side of the technology. Being able to make a gun with a 3D printer is very scary. Having gun CAD data online for people to "print" functional weapons is truly scary. I am an advocate for open source software and hardware but printing guns and other weapons and sharing them freely online I'm totally against it.

Good points, Mrdon. But I don't this genie will go back into its bottle. Yet really, guns are so easy to come by, I don't believe 3D guns will amount to much when it comes to criminals or the deranged.

This makes it possible to print the lower receiver of a AR-15 automatic, but are we getting closer to having an entire gun that can be made from plastic (whether from a 3D printer or not)? For more than a decade, spy movies and novels have depicted the use of plastic and ceramic guns as a means of beating metal detectors at airports, but the NRA has said that such guns are fiction. So now, are we looking at the possibility of plastic guns, as well as plastic guns made by 3D printers? Would this mean anything for airport security? Or do full-body scanners eliminate those issues?

I think you all are raising great points. I certainly agree that this technology opens up a Pandora's Box, but I suppose the box was already open and a criminal with a plan is going to find some way to pull it off, whether he opts for this kind of DIY method or finds some avenue to purchase weaponry. And as many of you point out, technology always comes with a dark side. It's just that this dark side is pretty dark.

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